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Date: Thu, 31 Aug 2017 10:56:07 +0200
From: Boris Brezillon <boris.brezillon@...e-electrons.com>
To: Ingo van Lil <inguin@....de>
Cc: linux-kernel@...r.kernel.org,
Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
Nicolas Ferre <nicolas.ferre@...el.com>,
linux-clk@...r.kernel.org
Subject: Re: [PATCH] clk: at91: utmi: Support configurable multipliers
Hi Ingo,
Sorry for the delay.
On Mon, 10 Jul 2017 14:24:09 +0200
Ingo van Lil <inguin@....de> wrote:
> The AT91 UTMI clock is a PLL generating the 480 MHz USB clock.
> Originally, this PLL always had a fixed x40 multiplier, thus requiring
> a 12 MHz input clock. Recent SOCs (sama5d2 and sama5d3) have a special
> function register for configuring this multiplier, allowing to use
> different main clock frequencies.
Looks good to me, just a few nitpicks below. Once addressed you can add
Acked-by: Boris Brezillon <boris.brezillon@...e-electrons.com>
>
> Signed-off-by: Ingo van Lil <inguin@....de>
> ---
> drivers/clk/at91/clk-utmi.c | 105 +++++++++++++++++++++++++++++++++++++++++--
> include/soc/at91/atmel-sfr.h | 2 +
> 2 files changed, 104 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/clk/at91/clk-utmi.c b/drivers/clk/at91/clk-utmi.c
> index aadabd9..d41c38b 100644
> --- a/drivers/clk/at91/clk-utmi.c
> +++ b/drivers/clk/at91/clk-utmi.c
> @@ -14,14 +14,29 @@
> #include <linux/of.h>
> #include <linux/mfd/syscon.h>
> #include <linux/regmap.h>
> +#include <soc/at91/atmel-sfr.h>
>
> #include "pmc.h"
>
> +/* default multiplier for SOCs that do not allow configuration via SFR */
> #define UTMI_FIXED_MUL 40
>
> +/* supported multiplier settings for SOCs that allow configuration via SFR */
> +struct utmi_multipliers {
> + const char *sfr_compatible_name;
const char *sfr_compat;
so that you don't end with formatting issues because of the 80 chars
per line rule.
> + u8 multipliers[4];
> +};
> +
> +static const struct utmi_multipliers utmi_multipliers[] = {
> + { "atmel,sama5d2-sfr", { 40, 30, 20, 40 } },
> + { "atmel,sama5d3-sfr", { 40, 30, 20, 10 } },
> +};
> +
> struct clk_utmi {
> struct clk_hw hw;
> struct regmap *regmap;
> + struct regmap *sfr_regmap;
> + const u8 *multipliers;
> };
>
> #define to_clk_utmi(hw) container_of(hw, struct clk_utmi, hw)
> @@ -66,8 +81,67 @@ static void clk_utmi_unprepare(struct clk_hw *hw)
> static unsigned long clk_utmi_recalc_rate(struct clk_hw *hw,
> unsigned long parent_rate)
> {
> - /* UTMI clk is a fixed clk multiplier */
> - return parent_rate * UTMI_FIXED_MUL;
> + struct clk_utmi *utmi = to_clk_utmi(hw);
> + u8 mul = UTMI_FIXED_MUL;
> +
> + if (utmi->sfr_regmap && utmi->multipliers) {
> + u32 regval;
Add an empty line here.
> + regmap_read(utmi->sfr_regmap, AT91_SFR_UTMICKTRIM, ®val);
> + mul = utmi->multipliers[regval & AT91_UTMICKTRIM_FREQ_MASK];
> + }
> +
> + return parent_rate * mul;
> +}
> +
> +static long clk_utmi_round_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long *parent_rate)
> +{
> + struct clk_utmi *utmi = to_clk_utmi(hw);
> + unsigned long bestrate = 0;
> + int bestdiff = -1;
> + int i;
> +
> + if (!utmi->sfr_regmap || !utmi->multipliers)
> + return *parent_rate * UTMI_FIXED_MUL;
> +
> + for (i = 0; i < ARRAY_SIZE(utmi_multipliers); i++) {
> + unsigned long tmprate = *parent_rate * utmi->multipliers[i];
> + int tmpdiff;
> +
> + if (tmprate < rate)
> + continue;
> +
> + tmpdiff = tmprate - rate;
> + if (bestdiff < 0 || bestdiff > tmpdiff) {
> + bestrate = tmprate;
> + bestdiff = tmpdiff;
> + }
> +
> + if (!bestdiff)
> + break;
> + }
> +
> + return bestrate;
> +}
> +
> +static int clk_utmi_set_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long parent_rate)
> +{
> + struct clk_utmi *utmi = to_clk_utmi(hw);
> + int i;
> +
> + if (!utmi->sfr_regmap || !utmi->multipliers)
> + return rate == parent_rate * UTMI_FIXED_MUL ? 0 : -EINVAL;
> +
> + for (i = 0; i < ARRAY_SIZE(utmi_multipliers); i++) {
> + if (rate == parent_rate * utmi->multipliers[i]) {
> + regmap_update_bits(utmi->sfr_regmap, AT91_SFR_UTMICKTRIM,
> + AT91_UTMICKTRIM_FREQ_MASK, i);
> + return 0;
> + }
> + }
> +
> + return -EINVAL;
> }
>
> static const struct clk_ops utmi_ops = {
> @@ -75,10 +149,13 @@ static const struct clk_ops utmi_ops = {
> .unprepare = clk_utmi_unprepare,
> .is_prepared = clk_utmi_is_prepared,
> .recalc_rate = clk_utmi_recalc_rate,
> + .round_rate = clk_utmi_round_rate,
> + .set_rate = clk_utmi_set_rate,
> };
>
> static struct clk_hw * __init
> at91_clk_register_utmi(struct regmap *regmap,
> + struct regmap *sfr_regmap, const u8 *multipliers,
> const char *name, const char *parent_name)
> {
> struct clk_utmi *utmi;
> @@ -98,6 +175,8 @@ at91_clk_register_utmi(struct regmap *regmap,
>
> utmi->hw.init = &init;
> utmi->regmap = regmap;
> + utmi->sfr_regmap = sfr_regmap;
> + utmi->multipliers = multipliers;
>
> hw = &utmi->hw;
> ret = clk_hw_register(NULL, &utmi->hw);
> @@ -115,6 +194,9 @@ static void __init of_at91sam9x5_clk_utmi_setup(struct device_node *np)
> const char *parent_name;
> const char *name = np->name;
> struct regmap *regmap;
> + struct regmap *sfr_regmap;
> + const u8 *multipliers = NULL;
> + size_t i;
>
> parent_name = of_clk_get_parent_name(np, 0);
>
> @@ -124,7 +206,24 @@ static void __init of_at91sam9x5_clk_utmi_setup(struct device_node *np)
> if (IS_ERR(regmap))
> return;
>
> - hw = at91_clk_register_utmi(regmap, name, parent_name);
> + for (i = 0; i < ARRAY_SIZE(utmi_multipliers); i++) {
> + sfr_regmap = syscon_regmap_lookup_by_compatible(
> + utmi_multipliers[i].sfr_compatible_name);
const char *compat = utmi_multipliers[i].sfr_compat;
sfr_regmap = syscon_regmap_lookup_by_compatible(compat);
This way you avoid this weird formatting.
> + if (!IS_ERR(sfr_regmap)) {
> + pr_debug("clk-utmi: found sfr node: %s\n",
> + utmi_multipliers[i].sfr_compatible_name);
> + multipliers = utmi_multipliers[i].multipliers;
> + break;
> + }
> + }
> +
> + if (IS_ERR(sfr_regmap)) {
> + pr_debug("clk-utmi: failed to find sfr node\n");
> + sfr_regmap = NULL;
> + }
> +
> + hw = at91_clk_register_utmi(regmap, sfr_regmap, multipliers,
> + name, parent_name);
> if (IS_ERR(hw))
> return;
>
> diff --git a/include/soc/at91/atmel-sfr.h b/include/soc/at91/atmel-sfr.h
> index 506ea8f..763948e 100644
> --- a/include/soc/at91/atmel-sfr.h
> +++ b/include/soc/at91/atmel-sfr.h
> @@ -17,6 +17,7 @@
> /* 0x08 ~ 0x0c: Reserved */
> #define AT91_SFR_OHCIICR 0x10 /* OHCI INT Configuration Register */
> #define AT91_SFR_OHCIISR 0x14 /* OHCI INT Status Register */
> +#define AT91_SFR_UTMICKTRIM 0x30 /* UTMI Clock Trimming Register */
> #define AT91_SFR_I2SCLKSEL 0x90 /* I2SC Register */
>
> /* Field definitions */
> @@ -28,5 +29,6 @@
> AT91_OHCIICR_SUSPEND_B | \
> AT91_OHCIICR_SUSPEND_C)
>
> +#define AT91_UTMICKTRIM_FREQ_MASK 0x03
>
> #endif /* _LINUX_MFD_SYSCON_ATMEL_SFR_H */
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